Noise exposure levels and associated effects among workers in heavy machine maintenance workshops; a study in gold mining site

Abstract

ABSTRACT Background: Mining sector is among the fastest growing economies worldwide. The processes associated with mining activities generate tremendous noise. Excessive noise exposure in the workplace can limit worker’s ability to communicate and hear warning signals as well as temporary hearing problems and permanent noise induced hearing loss. This may have huge impact on worker’s safety and productivity. Objective: This study assessed Noise Exposure Levels and Associated Effects among Heavy Machine Maintenance Workshop workers in Gold Mine Site in Tanzania. Methods: One hundred and nineteen (119) workers at maintenance workshop in gold mine site participated in this cross-sectional study. Information on demographic characteristics, hearing problems experienced and attitudes toward hearing protective devices were collected using questionnaire. Personal noise exposure levels (n=62) and area noise levels (n=18) were measured were measured using Larson Davis noise dosimeters. Frequencies were generated, logistic regression and chi-square test were used to determine association of the study variables. Results: All respondents were male with arithmetic mean age 35.1, the mean noise exposure level was 85.68 dB(A). Among workers with recent audiometry, 3.2% had severe hearing loss that required referral, 12.9% had moderate hearing loss (warning level). Prevalence of self-reported hearing problems was (56.5%) for workers with noise exposure of above 85 dB (A). Major hearing problems reported include speech interference (7%), reduction in hearing (56%) tinnitus (31%) and ear infections (6%). About 93.3% of workers regularly using hearing protection devices. Factors associated with hearing problems include noise exposure levels (AOR=1.71,p=0.002),age (AOR=2.01,p=0.005), exposure duration (AOR=1.91,p=0.009), organic solvent use (AOR=1.20,p=0.009) and hearing protection device usage (AOR=1.87,p=0.025)

Conclusion: Findings from this study indicate workers in maintenance workshop at gold mine site were exposed to noise levels higher than the occupational exposure limit (OEL) and may develop hearing problems like any other workers in the mine.

Recommendations: The mine management should institute more measures like regular training on hearing protection devices use and hearing conservation program to reduce the risk of developing noise induced hearing loss.